Show "Restore Checkpoint" only when there were changes (#27243)

Release Notes:

- N/A

---------

Co-authored-by: Agus Zubiaga <hi@aguz.me>
Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>

crates/fs/src/fake_git_repo.rs

@@ -420,4 +420,13 @@ impl GitRepository for FakeGitRepository {
     ) -> BoxFuture<Result<()>> {
         unimplemented!()
     }
+
+    fn compare_checkpoints(
+        &self,
+        _left: GitRepositoryCheckpoint,
+        _right: GitRepositoryCheckpoint,
+        _cx: AsyncApp,
+    ) -> BoxFuture<Result<bool>> {
+        unimplemented!()
+    }
 }